Hydrophobic Polydimethylsiloxane (PDMS) Coating of Mesoporous Silica and Its Use as a Preconcentrating Agent of Gas Analytes

Abstract

Mesoporous silica with mean pore size of ∼14 nm was coated by polydimethylsiloxane (PDMS) using a thermal deposition method. We showed that the inner walls of pores larger than ∼8 nm can be coated by thin layers of PDMS, and the surfaces consisting of PDMS-coated silica were superhydrophobic, with water contact angles close to 170°. We used the PDMS-coated silica as adsorbents of various gas-phase chemical warfare agent (CWA) simulants. PDMS-coated silica allowed molecular desorption of various CWA simulants even after exposure under highly humid conditions and, therefore, is applicable as an agent for the preconcentration of gas-phase analytes to enhance the sensitivities of various sensors.

Bioelastomers Based on Cocoa Shell Waste with Antioxidant Ability

“…The performance of silicone polymers is strongly dependent on the curing state of PDMS network . In situ ATR‐FTIR measurements were carried out to determine the effect of micronized CSW powder in the curing behavior of the bioelastomers following the consumption of acetoxy groups at ≈1750 cm −1 during the cross‐linking process, Figure S1a (Supporting Information).…”

“…WVTR and WVP, calculated according to Equations and , increased when micronized CSW concentration was increased. Because of its hydrophobic nature and well cross‐linked structure, pure PDMS films exhibited the lowest WVTR (100.1 g (m −2 d −1 )) and WVP (1.45 × 10 −5 g (m d Pa) −1 ). Despite the fact that CSW contains various hydrophilic compounds (such as polysaccharides, proteins, etc …”

Robust hybrid elastomer/metal-oxide superhydrophobic surfaces

“…However, so far the structuring of the PDMS surface has mostly resulted in a sticky Wenzel state, [20][21][22] and in order to achieve real superhydrophobicity a hydrophobic coating was still needed to keep droplets in the Cassie state. 11,[23][24][25][26][27][28][29][30][31][32] Various direct write and replication methods have been employed to micro/nanostructure bulk hydrophobic materials. Replication methods such as casting a polymer solution or melt on a template, 33,34 injection moulding, [35][36][37] hot embossing, 38,39 and sacrificial etching 7,40,41 have been utilized.…”

Oil–Water Separation Using Superhydrophobic PET Membranes Fabricated Via Simple Dip‐Coating Of PDMS–SiO2 Nanoparticles

“…PDMS‐coated SiO 2 for the fabrication of a dip‐coating solution was prepared using a thermal vapor deposition method . Fluidic PDMS and SiO 2 nanoparticles were placed in a stainless steel reactor with a weight ratio of 3:1 (we used 900 g of PDMS and 300 g of SiO 2 ), and separated using a metal mesh partition (with PDMS on the bottom of the chamber and SiO 2 on top of the mesh partition).…”